A new fundamental type of conformational isomerism

Abstract

Isomerism is a fundamental chemical concept, reflecting the fact that the arrangement of atoms in a molecular entity has a profound influence on its chemical and physical properties. Here we describe a previously unclassified fundamental form of conformational isomerism through four resolved stereoisomers of a transoid (BF)O(BF)-quinoxalinoporphyrin. These comprise two pairs of enantiomers that manifest structural relationships not describable within existing IUPAC nomenclature and terminology. They undergo thermal diastereomeric interconversion over a barrier of 104 ± 2 kJ mol−1, which we term ‘akamptisomerization’. Feasible interconversion processes between conceivable synthesis products and reaction intermediates were mapped out by density functional theory calculations, identifying bond-angle inversion (BAI) at a singly bonded atom as the reaction mechanism. We also introduce the necessary BAI stereodescriptors parvo and amplo. Based on an extended polytope formalism of molecular structure and stereoisomerization, BAI-driven akamptisomerization is shown to be the final fundamental type of conformational isomerization.

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Fig. 1: Isomerism hierarchy.
Fig. 2: BAI processes within single bonds.
Fig. 3: Synthesis, structures and nomenclature of the eight possible stereoisomers produced by reaction of quinoxalinoporphyrin 1.
Fig. 4: Energetics of akamptisomerization.

Change history

  • 27 July 2018

    In the version of this Article originally published, the word ‘stereoisomerism’ was erroneously included in the label of the upper-right box of Fig. 1. The label within the box has been corrected and it now reads: “Constitutional isomerism (same formula, different connectivity)”. This has been corrected in the online version of the Article.

References

  1. 1.

    McNaught, A. D. & Wilkinson, A. IUPAC Compendium of Chemical Terminology — The Gold Book 2nd edn (Blackwell, Oxford, 1997).

  2. 2.

    Testa, B., Caldwell, J. & Kisakürek, M. V. Organic stereochemistry: guiding principles and bio-medicinal relevance. A general introduction to the series. Helv. Chim. Acta 96, 1–3 (2013).

    Article  CAS  Google Scholar 

  3. 3.

    Testa, B., Vistoli, G. & Pedretti, A. Organic stereochemistry. Part 1. Symmetry elements and operations, classification of stereoisomers. Helv. Chim. Acta 96, 4–30 (2013).

    Article  CAS  Google Scholar 

  4. 4.

    Testa, B. Organic stereochemistry. Part 2. Stereoisomerism resulting from one or several stereogenic centers. Helv. Chim. Acta 96, 159–188 (2013).

    Article  CAS  Google Scholar 

  5. 5.

    Testa, B. Organic stereochemistry. Part 3. Other stereogenic elements: axes of chirality, planes of chirality, helicity, and (E,Z)-diastereoisomerism. Helv. Chim. Acta 96, 351–374 (2013).

    Article  CAS  Google Scholar 

  6. 6.

    Testa, B., Vistoli, G. & Pedretti, A. Organic stereochemistry. Part 4. Isomerisms about single bonds and in cyclic systems. Helv. Chim. Acta 96, 564–623 (2013).

    Article  CAS  Google Scholar 

  7. 7.

    Testa, B., Vistoli, G., Pedretti, A. & Caldwell, J. Organic stereochemistry. Part 5. Stereoselectivity in molecular and clinical pharmacology. Helv. Chim. Acta 96, 747–798 (2013).

    Article  CAS  Google Scholar 

  8. 8.

    Vistoli, G., Testa, B. & Pedretti, A. Organic stereochemistry. Part 6. The conformation factor in molecular pharmacology. Helv. Chim. Acta 96, 1005–1031 (2013).

    Article  CAS  Google Scholar 

  9. 9.

    Testa, B. Organic stereochemistry. Part 7. The concept of substrate stereoselectivity in biochemistry and xenobiotic metabolism. Helv. Chim. Acta 96, 1203–1234 (2013).

    Article  CAS  Google Scholar 

  10. 10.

    Testa, B. Organic stereochemistry. Part 8. Prostereoisomerism and the concept of product stereoselectivity in biochemistry and xenobiotic metabolism. Helv. Chim. Acta 96, 1409–1451 (2013).

    Article  CAS  Google Scholar 

  11. 11.

    King, H. The possibility of a new instance of optical activity without an asymmetric carbon atom. Proc. Chem. Soc. Lond. 30, 249–251 (1914).

    CAS  Google Scholar 

  12. 12.

    Cain, J. C. & Micklethwait, F. M. G. Studies in the diphenyl series. Part VI. The configuration of diphenyl and its derivatives. J. Chem. Soc. Trans. 105, 1437–1441 (1914).

    Article  CAS  Google Scholar 

  13. 13.

    Christie, G. H. & Kenner, J. The molecular configurations of polynuclear aromatic compounds. Part I. The resolution of γ-6:6′-dinitro- and 4:6:4′:6′-tetranitro-diphenic acids into optically active components. J. Chem. Soc. Trans. 121, 614–620 (1922).

    Article  CAS  Google Scholar 

  14. 14.

    Kuhn, R. In Molekulare Asymmetrie 803–824 (Franz-Deutike, Leipzig, 1933).

  15. 15.

    Horner, L. et al. Phosphororganische verbindungen optisch aktive tertiäre Phosphine aus optisch aktiven quartären Phosphoniumsalzen. Tetrahedron Lett. 2, 161–166 (1961).

    Article  Google Scholar 

  16. 16.

    Brois, S. J. Aziridines. XII. Isolation of a stable nitrogen pyramid. J. Am. Chem. Soc. 90, 508–509 (1968).

    Article  CAS  Google Scholar 

  17. 17.

    Muetterties, E. L. Topological representation of stereoisomerism. I. Polytopal rearrangements. J. Am. Chem. Soc. 91, 1636–1643 (1969).

    Article  CAS  Google Scholar 

  18. 18.

    Muetterties, E. L. & Storr, A. T. Topological analysis of polytopal rearrangements. Sufficient conditions for closure. J. Am. Chem. Soc. 91, 3098–3099 (1969).

    Article  CAS  Google Scholar 

  19. 19.

    Muetterties, E. L. Topological representation of stereoisomerism. II The five-atom family. J. Am. Chem. Soc. 91, 4115–4122 (1969).

    Article  CAS  Google Scholar 

  20. 20.

    Meakin, P. et al. Structure and stereochemical nonrigidity of six-coordinate complexes. J. Am. Chem. Soc. 92, 3482–3484 (1970).

    Article  CAS  Google Scholar 

  21. 21.

    Muetterties, E. L., Wiersema, R. J. & Hawthorne, M. F. Detection of polytopal isomers in the solution state. I. Eight-atom family. J. Am. Chem. Soc. 95, 7520–7522 (1973).

    Article  CAS  Google Scholar 

  22. 22.

    Muetterties, E. L. & Guggenberger, L. J. Idealized polytopal forms. Description of real molecules referenced to idealized polygons or polyhedra in geometric reaction path form. J. Am. Chem. Soc. 96, 1748–1756 (1974).

    Article  CAS  Google Scholar 

  23. 23.

    Muetterties, E. L. Polytopal form and isomerism. Tetrahedron 30, 1595–1604 (1974).

    Article  CAS  Google Scholar 

  24. 24.

    Guggenberger, L. J. & Muetterties, E. L. Reaction path analysis. 2. The nine-atom family. J. Am. Chem. Soc. 98, 7221–7225 (1976).

    Article  CAS  Google Scholar 

  25. 25.

    Hoffmann, R., Beier, B. F., Muetterties, E. L. & Rossi, A. R. Seven-coordination. A molecular orbital exploration of structure, stereochemistry, and reaction dynamics. Inorg. Chem. 16, 511–522 (1977).

    Article  CAS  Google Scholar 

  26. 26.

    Debolt, L. C. & Mark, J. E. Effects of bond-angle inversion on the statistical properties of poly(dimethylsiloxane). J. Polym. Sci. B 26, 989–995 (1988).

    Article  CAS  Google Scholar 

  27. 27.

    Kalinowski, H.-O. & Kessler, H. in Topics in Stereochemistry Vol. 7 (eds Allinger, N. L. & Eliel, E. l.) 295–384 (Wiley Interscience, New York, 1973).

  28. 28.

    Kessler, H. Thermal isomerization about double bonds. Rotation and inversion. Tetrahedron 30, 1861–1870 (1974).

    Article  CAS  Google Scholar 

  29. 29.

    Gozlan, H., Michelot, R., Riche, C. & Rips, R. Amide-oximes: determination des configurations et etude du mecanisme de l’isomerisation ZE. Tetrahedron 33, 2535–2542 (1977).

    Article  CAS  Google Scholar 

  30. 30.

    Bakhmutov, V. I. et al. A dynamic NMR study of Z,E‐isomerization in solutions of indolyl‐substituted α‐nitroacrylates. Org. Magn. Reson. 11, 308–312 (1978).

    Article  CAS  Google Scholar 

  31. 31.

    Appenroth, K., Reichenbächer, M. & Paetzold, R. Thermochromism and photochromism of aryl-substituted acyclic azines.Tetrahedron 37, 569–573 (1981).

    Article  CAS  Google Scholar 

  32. 32.

    Kirste, K. & Rademacher, P. Rotation and inversion in nitrosamines. J. Mol. Struct. 73, 171–180 (1981).

    Article  CAS  Google Scholar 

  33. 33.

    Sammes, M. P. The effect of salt formation on structure and charge distribution in imines. Part 4. Energy barriers to isomerisation about the C–N bond in 2,6-dimethyl-4-aryliminopyrans and their salts: solvent and substituent effects, and evidence for isomerisation mechanisms. J. Chem. Soc., Perkin Trans. 2, 1501–1507 (1981).

    Article  Google Scholar 

  34. 34.

    Kawada, Y. & Iwamura, H. Bis(4-chloro-1-triptycyl) ether. Separation of a pair of phase isomers of labeled bevel gears. J. Am. Chem. Soc. 103, 958–960 (1981).

    Article  CAS  Google Scholar 

  35. 35.

    Gustav, K., Vettermann, S. & Birner, P. Quantum chemical studies on colour and stereodynamics of acyclic azines. Part IX. The coupled N–N rotation/N inversion mechanism for the thermal (E,Z) isomerization of benzaldazine. THEOCHEM 88, 249–253 (1982).

    Article  Google Scholar 

  36. 36.

    Kawada, Y. & Iwamura, H. Correlated rotation in bis(9-triptycyl)methanes and bis(9-triptycyl) ethers. Separation and interconversion of the phase isomers of labeled bevel gears. J. Am. Chem. Soc. 105, 1449–1459 (1983).

    Article  CAS  Google Scholar 

  37. 37.

    Cunningham, I. D. & Hegarty, A. F. Acid, base, and uncatalysed isomerisation of Z- to E-amidine. A mechanistic study. J. Chem. Soc., Perkin Trans. 2, 537–541 (1986).

    Article  Google Scholar 

  38. 38.

    Frenna, V., Buscemi, S., Spinelli, D. & Consiglio, G. A kinetic study on the base-catalysed EZ isomerization of some arylhydrazones of 3-benzoyl-5-phenyl-1,2,4-oxadiazole: effect of the substituents in the arylhydrazone moiety. J. Chem. Soc., Perkin Trans. 2, 215–221 (1990).

    Article  Google Scholar 

  39. 39.

    Gáplovský, A., Donovalová, J., Lacová, M., Mračnová, R. & El-Shaaer, H. M. The photochemical behaviour of 6-X-4H-3(bicyclo[2.2.1]-5-heptene-2,3-dicarboximidoiminomethyl)-4-chromones. Photochromism and thermochromism. J. Photochem. Photobiol., A 136, 61–65 (2000).

    Article  Google Scholar 

  40. 40.

    Sung, K. N-substituent effects on the stability of ketenimines. J. Chem. Soc., Perkin Trans. 2, 847–852 (2000).

    Article  Google Scholar 

  41. 41.

    Klika, K. D. et al. Configuration and E/Z interconversion mechanism of O(S)-allyl-S(O)-methyl-N-(acridin-9-yl)-iminothiocarbonate. Magn. Reson. Chem. 43, 380–388 (2005).

    Article  CAS  PubMed  Google Scholar 

  42. 42.

    Pirozhenko, V. V., Rozhenko, A. B., Avdeenko, A. P., Konovalova, S. A. & Santalova, A. A. Z,E-isomerization mechanism for N-arylthio-1,4-benzoquinonimines: DNMR and DFT investigations. Magn. Reson. Chem. 46, 811–817 (2008).

    Article  CAS  PubMed  Google Scholar 

  43. 43.

    Landge, S. M. et al. Isomerization mechanism in hydrazone-based rotary switches: Lateral shift, rotation, or tautomerization? J. Am. Chem. Soc. 133, 9812–9823 (2011).

    Article  CAS  PubMed  Google Scholar 

  44. 44.

    Luo, Y. et al. Cistrans isomerisation of substituted aromatic imines: a comparative experimental and theoretical study. ChemPhysChem 12, 2311–2321 (2011).

    Article  CAS  PubMed  Google Scholar 

  45. 45.

    Greb, L., Eichhöfer, A. & Lehn, J. M. Synthetic molecular motors: thermal N inversion and directional photoinduced C=N bond rotation of camphorquinone imines. Angew. Chem. Int. Ed. 54, 14345–14348 (2015).

    Article  CAS  Google Scholar 

  46. 46.

    Belcher, W. J., Boyd, P. D. W., Brothers, P. J., Liddell, M. J. & Rickard, C. E. F. J. Am. Chem. Soc. 116, 8416–8417 (1994).

    Article  CAS  Google Scholar 

  47. 47.

    Belcher, W. J., Breede, M., Brothers, P. J. & Rickard, C. E. F. The porphyrin as a binucleating ligand: preparation and crystal structure of a porphyrin complex containing a coordinated B2O2 ring. Angew. Chem. Int. Ed. 37, 1112–1114 (1998).

    Article  CAS  Google Scholar 

  48. 48.

    Brothers, P. J. Organometallic chemistry of main group porphyrin complexes. Adv. Organomet. Chem. 48, 289–295 (2001).

    Article  CAS  Google Scholar 

  49. 49.

    Brothers, P. J. Recent developments in the coordination chemistry of porphyrin complexes containing non-metallic and semi-metallic elements. J. Porphyr. Phthalocyanines 6, 259–267 (2002).

    Article  CAS  Google Scholar 

  50. 50.

    Köhler, T.et al. Octaethylporphyrin and expanded porphyrin complexes containing coordinated BF2 groups. Chem. Commun.1060–1061 (2004).

  51. 51.

    Albrett, A. M., Boyd, P. D. W., Clark, G. R., Gonzalez, E. & Brothers, P. J. Reductive coupling and protonation leading to diboron corroles with a B–H–B bridge. Dalton Trans. 39, 4032–4034 (2010).

    Article  CAS  PubMed  Google Scholar 

  52. 52.

    Belcher, W. J. et al. Porphyrin complexes containing coordinated BOB groups: synthesis, chemical reactivity and the structure of [BOB(tpClpp)]2+. Dalton Trans., 1602–1614 (2008).

  53. 53.

    Brothers, P. J. Boron complexes of porphyrins and related polypyrrole ligands: unexpected chemistry for both boron and the porphyrin. Chem. Commun. 2090–2102 (2008).

  54. 54.

    Albrett, A. Synthesis of Boron Corrole Complexes. PhD thesis, Univ. Auckland (2009).

  55. 55.

    Brothers, P. J. Boron complexes of pyrrolyl ligands. Inorg. Chem. 50, 12374–12386 (2011).

    Article  CAS  PubMed  Google Scholar 

  56. 56.

    Albrett, A. M. et al. Mono- and diboron corroles: factors controlling stoichiometry and hydrolytic reactivity. Inorg. Chem. 53, 5486–5493 (2014).

    Article  CAS  PubMed  Google Scholar 

  57. 57.

    Weiss, A., Hodgson, M. C., Boyd, P. D. W., Siebert, W. & Brothers, P. J. Diboryl and diboranyl porphyrin complexes: synthesis, structural motifs, and redox chemistry: diborenyl porphyrin or diboranyl isophlorin? Chem. Eur. J. 13, 5982–5993 (2007).

    Article  CAS  PubMed  Google Scholar 

  58. 58.

    Albrett, A. M. et al. Corrole as a binucleating ligand: preparation, molecular structure and density functional theory study of diboron corroles. J. Am. Chem. Soc. 130, 2888–2889 (2008).

    Article  CAS  PubMed  Google Scholar 

  59. 59.

    Albrett, A. M., Conradie, J., Ghosh, A. & Brothers, P. J. DFT survey of monoboron and diboron corroles: regio- and stereochemical preferences for a constrained, low-symmetry macrocycle. Dalton Trans. 4464–4473 (2008).

  60. 60.

    Crossley, M. J., Sintic, P. J., Walton, R. & Reimers, J. R. Synthesis and physical properties of biquinoxalinyl bridged bis-porphyrins: models for aspects of photosynthetic reaction centres. Org. Biomol. Chem. 1, 2777–2787 (2003).

    Article  CAS  PubMed  Google Scholar 

  61. 61.

    Kadish, K. M. et al. Quinoxalino[2,3-b′]porphyrins behave as π-expanded porphyrins upon one-electron reduction: broad control of the degree of delocalization through substitution at the macrocycle periphery. J. Phys. Chem. B 111, 8762–8774 (2007).

    Article  CAS  PubMed  Google Scholar 

  62. 62.

    Sintic, P. J. et al. Control of the site and potential of reduction and oxidation processes in π-expanded quinoxalinoporphyrins. Phys. Chem. Chem. Phys. 10, 268–280 (2008).

    Article  CAS  PubMed  Google Scholar 

  63. 63.

    Hartshorn, R. The red book – nomenclature of inorganic chemistry. IUPAC Recommendations 2005. Chem. Int. 29, 14–16 (2007).

    CAS  Google Scholar 

  64. 64.

    Dixon, H. B. F. et al. Nomenclature of tetrapyrroles. Pure Appl. Chem. 59, 779–832 (1987).

    Article  CAS  Google Scholar 

  65. 65.

    Goerigk, L. & Sharma, R. The INV24 test set: how well do quantum-chemical methods describe inversion and racemization barriers? Can. J. Chem. 94, 1133–1143 (2016).

    Article  CAS  Google Scholar 

  66. 66.

    Krausz, E. Selective and differential optical spectroscopies in photosynthesis. Photosynth. Res. 116, 411–426 (2013).

    Article  CAS  PubMed  Google Scholar 

  67. 67.

    Scott, D. R. S. & Allison, J. B. Solvent glasses for low temperature spectroscopic studies. J. Phys. Chem. 66, 561–562 (1962).

    Article  CAS  Google Scholar 

  68. 68.

    Reimers, J. R. & Krausz, E. An analytical data inversion method for magnetic circular dichroism spectra dominated by the ‘B-term’. Phys. Chem. Chem. Phys. 16, 2315–2322 (2014).

    Article  CAS  PubMed  Google Scholar 

  69. 69.

    Sendt, K. et al. Switchable electronic coupling in oligoporphyrin molecular wires examined through the measurement and assignment of electronic absorption spectra. J. Am. Chem. Soc. 124, 9299–9309 (2002).

    Article  CAS  PubMed  Google Scholar 

  70. 70.

    Becke, A. D. Density-functional thermochemistry. III. The role of exact exchange. J. Chem. Phys. 98, 5648–5652 (1993).

    Article  CAS  Google Scholar 

  71. 71.

    Yanai, T., Tew, D. P. & Handy, N. C. A new hybrid exchange-correlation functional using the Coulomb-attenuating method (CAM-B3LYP). Chem. Phys. Lett. 393, 51–57 (2004).

    Article  CAS  Google Scholar 

  72. 72.

    Kobayashi, R. & Amos, R. D. The application of CAM-B3LYP to the charge-transfer band problem of the zincbacteriochlorin–bacteriochlorin complex. Chem. Phys. Lett. 420, 106–109 (2006).

    Article  CAS  Google Scholar 

  73. 73.

    Cai, Z.-L., Crossley, M. J., Reimers, J. R., Kobayashi, R. & Amos, R. D. Density-functional theory for charge-transfer: the nature of the N-bands of porphyrins and chlorophylls revealed through CAM-B3LYP, CASPT2, and SAC-CI calculations. J. Phys. Chem. B 110, 15624–15632 (2006).

    Article  CAS  PubMed  Google Scholar 

  74. 74.

    Chai, J.-D. & Head-Gordon, M. Long-range corrected hybrid density functionals with damped atom-atom dispersion corrections. Phys. Chem. Chem. Phys. 10, 6615–6620 (2008).

    Article  CAS  PubMed  Google Scholar 

  75. 75.

    Foresman, J. B., Head-Gordon, M., Pople, J. A. & Frisch, M. J. towards a systematic molecular orbital theory for excited states. J. Phys. Chem. 96, 135 (1992).

    Article  CAS  Google Scholar 

  76. 76.

    Frisch, M. J. et al. Gaussian 09, Revision D.01 (Gaussian, 2009).

  77. 77.

    Goerigk, L. & Grimme, S. A thorough benchmark of density functional methods for general main group thermochemistry, kinetics, and noncovalent interactions. Phys. Chem. Chem. Phys. 13, 6670–6688 (2011).

    Article  CAS  PubMed  Google Scholar 

  78. 78.

    Tomasi, J., Mennucci, B. & Cammi, R. Quantum mechanical continuum solvation models. Chem. Rev. 105, 2999–3093 (2005).

    Article  CAS  Google Scholar 

  79. 79.

    Floris, F. M., Tomasi, J. & Pascual Ahuir, J. L. Dispersion and repulsion contributions to the solvation energy: refinements to a simple computational model in the continuum approximation. J. Comput. Chem. 12, 784–791 (1991).

    Article  CAS  Google Scholar 

  80. 80.

    Wolinski, K., Hinton, J. F. & Pulay, P. Efficient implementation of the gauge-independent atomic orbital method for NMR chemical shift calculations. J. Am. Chem. Soc. 112, 8251–8260 (1990).

    Article  CAS  Google Scholar 

  81. 81.

    Kobayashi, R. & Reimers, J. R. Free energies for the coordination of ligands to the magnesium of chlorophyll-a in solvents. Mol. Phys. 16, 928–932 (2015).

    Google Scholar 

  82. 82.

    Reimers, J. R. et al. Assignment of the Q-bands of the chlorophylls: coherence loss via Qx–Qy mixing. Sci. Rep. 3, 2761 (2013).

    Article  PubMed  PubMed Central  Google Scholar 

  83. 83.

    Werner, H.-J. et al. MOLPRO, Version 2015.1, A Package of Ab Initio Programs (Univ. Birmingham, 2015).

  84. 84.

    Dunning, T. H. Jr Gaussian basis sets for use in correlated molecular calculations I. The atoms boron through neon and hydrogen. J. Chem. Phys. 90, 1007 (1989).

    Article  CAS  Google Scholar 

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Acknowledgements

The authors thank the University of Sydney for a Gritton Scholarship, the Australian Research Council (grants DP0666378, DP0773847 and DP150103137), the National Natural Science Foundation of China (NSFC; grant no. 11674212) and the Shanghai High-End Foreign Experts Grant for funding this research, as well as National Computational Infrastructure (NCI, d63) and INTERSECT (r88) for the provision of computing resources. The authors also give special thanks to G. Price for his help with the Latin terms. This work is dedicated to the stereochemistry pioneers James Kenner FRS 1885-1974 and Kurt Mislow 1923–2017.

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P.J.C., J.R.R. and M.J.C. conceived and designed the overall project and wrote the manuscript. I.M.B. was primarily responsible for synthesis (with help from P.J.C. and M.J.C). I.J.L. designed and performed the NMR studies. P.J.C. performed the chiral resolutions, UV–vis, CD and MCD spectroscopies, along with E.K. (who also designed this). P.J.C performed all structural optimizations and NMR calculations, and Z.-L.C. and R.K. designed and performed the UV–vis spectral simulations with R.K. in particular focusing on the difficult question of accurate predictions of chirality. P.J.C. developed the application of the polytope formalism and the nomenclature study. The videos were prepared by P.J.C.

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Correspondence to Jeffrey R. Reimers or Maxwell J. Crossley.

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Supplementary information

Supplementary Information

Definitions of isomerization and polytope formalism; Synthesis and characterization; DFT calculations; Nomenclature considerations

Supplementary Video 1

Compounds 2a, 2b, 3a, 3b

Supplementary Video 2

Compounds 4a, 4b, 5a and 5b

Supplementary Video 3

BAI associated vibrational mode

Supplementary Video 4

BAI reaction coordinate

Supplementary Information

Cartesian coordinates of all optimized molecular structures

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Canfield, P.J., Blake, I.M., Cai, Z. et al. A new fundamental type of conformational isomerism. Nature Chem 10, 615–624 (2018). https://doi.org/10.1038/s41557-018-0043-6

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